A central step and a cost factor in the manufacturing of mineral binders, for example, cement, is that of grinding the large-particle mineral components into fine powder. During cement manufacturing, for example, clinker and, depending on the type of cement being manufactured, optionally also additives such as granulated slag or limestone, are ground into a fine powder. In this process, cement and additives can basically be ground together or separately.
The fineness of the mineral binder can be an important quality characteristic in this process. For example, cured mortar or concrete mixtures with fine-ground mineral binders generally have higher compressive strengths than corresponding mixtures on the basis of more coarsely ground mineral binders.
To facilitate the comminution of mineral binders in mills and to prevent agglomeration of the resulting powder particles, so-called grinding aids may be used. Grinding aids can bring about a marked reduction in the grinding time and in the energy input necessary for grinding. Since the 1960s, organic liquids, for example, glycols and amino alcohols, as well as mixtures thereof have provided good results as grinding aids. They are placed in the cement mill along with the material to be ground in quantities of up to about 0.1% of this material. In this way, the throughput of the mills can be increased by 20 to 30%, in some plants even by as much as 50%, at the same fineness and identical Blaine value of the cement.
So-called cement conditioners can also be used. These are substances which increase, for example, the compressive strengths of mortar or cement mixtures after curing. As a result, it is possible to achieve compressive strengths with less finely ground mineral binders comparable to those with more finely ground binders. Correspondingly, the mill throughputs can also be increased by the use of cement conditioners.
U.S. Pat. No. 5,084,103 (David F. Myers, W.R. Grace & Co.) in this connection describes for example, grinding aids and cement conditioners based on higher trialkanolamines such as triisopropanolamine, N,N-bis(2-hydroxyethyl)-N-2-hydroxypropyl)amine and tris(2-hydroxybutyl)amine.
A need exists for new and improved additives for the grinding of solids, for example, in the manufacturing of mineral binders.